bio

Plasma Membrane

The thin, flexible boundary between a cell and its environment that regulates the flow of materials and serves as a protective layer.

Fluid Mosaic Model

The widely accepted model of the plasma membrane, which describes its dynamic and flexible nature made up of different types of molecules.

Phospholipid Bilayer

The double layer of lipid molecules in the plasma membrane, with polar heads facing outside and nonpolar tails facing inside, creating a selectively permeable barrier.

Cholesterol

A membrane lipid that regulates the membrane's fluidity and permeability, preventing freezing or crystallization.

Glycolipids

Lipids with attached carbohydrate molecules that stabilize the cell membrane and facilitate communication between cells.

Integral Proteins

Membrane proteins that span the entire lipid layer, including channel proteins, receptor proteins, and glycoproteins.

Peripheral Proteins

Membrane proteins that mainly work with the cytoskeleton to support the cell, including enzymes and lipase.

Anchored Proteins/Lipid-Anchored Proteins

Membrane proteins bound to the membrane via covalent bonds, propagating signals and enhancing the activities of other proteins.

Cell Transport

The movement of substances across the cell membrane, including passive transport (simple diffusion, osmosis, facilitated diffusion) and active transport.

Simple Diffusion

The random movement of molecules from an area of high concentration to an area of low concentration without the input of energy.

Osmosis

The diffusion of water across a semi-permeable membrane, influenced by hypertonic, hypotonic, and isotonic solutions.

Facilitated Diffusion

The movement of ions and small molecules across the plasma membrane using transport proteins as facilitators.

Active Transport

The movement of molecules or particles against the concentration gradient with the use of energy or ATP, performed through pumps or vesicles.

Pumps

Carrier proteins that actively pump ions in and out of the cell, such as the Na-K pump.

Vesicle Transport

The use of vesicles to transport larger molecules and particles, including endocytosis (phagocytosis, pinocytosis) and exocytosis.

Vesicle Transport

The use of vesicles to move larger molecules and particles.

Endocytosis

The cellular process of moving a molecule or particle into the cell's cytoplasm.

Phagocytosis

The process of "cell eating" where a cell engulfs a solid particle through invagination.

Pinocytosis

The process of "cell drinking" where a cell takes in extremely small particles.

Exocytosis

The cellular process of releasing molecules or particles to the extracellular fluid.